Radon and radium in lake-bottoms can find drill targets, a powerful method of uranium exploration under lakes.

  • Radon and radium geochemistry of lake-bottom water and sediment is a detailed exploration tool in the Athabasca Sandstone and other areas where giant uranium deposits are found under lakes.
  • Gamma radiation is blocked by water, and under-lake uranium ore bodies and radioactive boulder trains cannot be detected by airborne or ground gamma-ray scintillometer or spectrometer surveys.
  • The Midwest Lake uranium deposit is under the lake and was found by drilling up-ice from a radioactive boulder train. When we sampled the surface water around the edge of Midwest Lake we found that the arm of the lake overlying the eventual discovery was anomalous in radon. See www.finderschoice.com/radon/midwest.php. It is likely that our radon anomaly is due either to the extension of the boulder train under the lake, or to broken up and weathered portions of the orebody on the lake bottom.
  • Had we run a grid over that arm of the lake, collected water samples near the bottom, and analysed them for radon, it is likely we would have defined a much smaller target suitable for drilling.
  • Collecting sediments and analysing for radium (or radon) would have refined the target even further. There is some evidence that uranium, being more soluble, is more readily leached from sediments, leaving an anomaly in radium but not un uranium. Link.
  • Movement of radon is limited by its 3.8-day half-life and its high solubility in water. There are no radon bubbles, and below the water table there is no mobile gas phase to scrub out and transport the radon. Precursors of radon in the uranium decay series, including radium with its 1622-year half-life, might be expected to diffuse farther than radon.
  • Equilibrium in the radium-radon pair occurs quickly with a half-life of 3.8 days, so that a radium anomaly is soon reflected by a radon anomaly. Uranium, on the other hand, takes a million years to grow into equilibrium with its daughter radon.
  • Once radon gets into the lake water it will not move into the sediments. It will not get trapped by clays or organics or get precipitated.
  • With our instruments, radon and radium analyses are available immediately in the field. Radon must be done within a week; radium can be done any time.

If chunks of ore and coarse sand are releasing radon into the water, then sampling fine sediments (like organics and clay) might miss the anomaly! We should also collect bottom water samples and analyse them for radon.

Robert H. Morse, Ph.D., P.Eng.
October 30, 2009
  • We measure: radon - radium - thoron - radon daughters - alpha radiation.
  • The Lucas cell is recognized as the most sensitive and reliable method for these elements.
  • Intrinsically safe functions.
  • Sensitive to geochemical trace levels necessary for radon in lake water and for radon-thoron isotope ratios.
  • immune to beta and gamma radiation.
  • one monitor works with a number of (less expensive) detectors.
  • Our instruments are used around the world in exploration for uranium, oil & gas, groundwater and hydrothermal, and in environmental protection, health physics, earthquake prediction, and evaluation of hydrocarbon and NAPL contamination etc.
  • Same instruments used for radon and radium in soil, sediment, plant parts, rocks, water, soil gas, air, snow, food, and for radon and thoron daughters in air.
  • Winter and summer, from the Sahara Desert to the Canadian Shield, our instruments have faced up to severe field conditions.
  • In the radon business since 1968, our instruments are updated regularly with the most recent major re-design in 2015. Modern, low-power, field-rugged electronics. Some earlier versions still working after 40 years.
  • Continuous real-time monitoring and data recording.
  • RS232 port/pc software.
  • User programmable measurement intervals, sample and count periods and alarm level settings.
  • Can work in a tent without electricity or be carried from point to point in the field.
  • 50 readings per day. Results available immediately.
  • Portable. Rechargeable battery pack good for a long day in the field and recharges in a few hours.
  • Can be operated by junior personnel if carefully supervised.
  • EPA and CE Mark compliant.
  • Click here (www.finderschoice.com/rn) for more details of our radon instruments, and for other instruments, components and accessories we provide.
  • Technical specification sheets and pictures of our instruments provided on request.
  • Multilingual consulting and training (if required).
For instruments contact

Click here for technical details and other applications of our radon instruments.

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